The invention relates to a method of venting a filled bottle which is closed by means of an elastic stopper. The invention also relates to an apparatus for venting a bottle which is closed by means of such a stopper.
The present invention is preferably used for small bottles for bottling pharmaceutical preparations, so-called vials.
When stoppers are positioned on bottles which are filled to a high level, an excess air pressure forms in the bottles. This excess pressure, en route between a stopper-positioning means and a flanging station, forces the stoppers out of the bottles again. These stoppers are consequently located loosely on the bottles. Owing to vibrations as the bottles are transported, stoppers fall into the bottling and packaging machine and cause much disruption there as a result. There is also the risk of the product becoming unsterile. Pressing-down stations, whether equipped with a push rod or with a roller, or else positive guide means are more or less ineffective and even involve new risks. Many stoppers can often be pressed manually into the bottles but are nevertheless forced out of the bottles again.
The elastic stoppers are connected, for example, to an extension of which the diameter is larger than the diameter of the stopper section inserted into the bottle opening. When the stopper has been fully inserted into the bottle opening, the extension butts against the bottle.
It is an object of the present invention to specify a method which is intended for venting a bottle which is closed by means of a stopper and which ensures that the stopper inserted into the bottle is not forced out of the bottle by excess pressure.
The invention proposes a method of venting a filled bottle which is closed by means of an elastic stopper, where the stopper inserted into the bottle opening is deformed such that an air-outlet opening is formed in the sealing region of the stopper and bottle.
The invention makes use of the finding that the excess pressure in the bottle which builds, when the stopper is inserted into the bottle, as a result of the high filling level of the bottle can be immediately dissipated by deformation of the stopper and thus the formation of an air-outlet opening between the stopper and bottle, this resulting in pressure equalization between the interior of the bottle and the atmosphere. There are consequently no compressive forces acting in the interior of the bottle which result in the stopper being forced out of the bottle. The problems described above in respect of further packaging of the bottle thus do not occur.
The stopper can be deformed even as it is inserted into the bottle. It would be sufficient, in principle, for the stopper to be deformed only once it has been inserted into the bottle. In the case of automated filling and packaging, however, it is expedient to overlap the stoppering operation and the venting operation. Immediately after the stopper has been fully inserted into the bottle, further packaging of the bottle can take place, for example in a flanging station.
In order to achieve the effect according to the invention, it is sufficient, in principle, to press laterally from one side against the extension projecting out of the bottle. The extension need not be elastic. All that is necessary is for it to be possible for a transverse force to be introduced, via the extension, into the stopper located in the top of the bottle.
The pressed stopper yields laterally because the deformation continues into the bottle and the air-outlet opening is thus formed.
Of course, the stopper may be configured without the extension, in which case the stopper partially projects out of the bottle when the latter is closed.
According to a preferred embodiment of the invention, it is provided that the squeezing forces are introduced into the stopper on sides of the latter which are directed away from one another. The clamping of the stopper which is produced in this way makes it possible, in particular during movement of the bottle with the stopper, to produce defined squeezing characteristics. This applies, in particular, when the bottle with the stopper positioned thereon is transported relative to a venting station and the stopper is squeezed transversely to the transporting direction.
It is also an object of the invention to provide an apparatus which is intended for implementing the method and which is of particularly straightforward construction.
In this context, it is proposed that the apparatus has a squeezing device which is arranged on at least one side of the stopper and is active in a direction parallel to the plane passing through the bottle opening. This squeezing means is arranged in particular on two sides of the stopper which are directed away from one another.
The apparatus according to the invention is used, in particular, in conjunction with a bottling and packaging station for bottles which are closed by means of stoppers, in particular vials which are closed by means of stoppers, in the case of which the operation of pressing the stoppers into the bottles is overlapped by the operation of venting the bottles.
It is regarded as being particularly advantageous if the apparatus has a body with a channel, where the channel is open at the start and at the end, the channel tapers and widens in width, and the width of the channel in its maximally tapered region is smaller than the diameter of the stopper region projecting out of the bottle, and where the lateral flanks of the channel form the squeezing device. During the operation of feeding the bottle with the stopper, the stopper region projecting out of the bottle at the top is consequently moved into the channel cone and squeezed on account of the dimensioning of the tapering channel width. In the adjoining, widening channel section, the squeezing forces are reduced and, finally, eliminated altogether, with the result that the elastic stopper can expand into the original rotationally symmetrical configuration. The body is, in particular, of plate-like design.
The body preferably has the channel on its underside. The body is consequently positioned above a transporting belt or a transporting apparatus for the bottles, and is, in particular, stationary.
A pressure-exerting device integrated into the body for pressing the stopper into the bottle opening is arranged, in particular, in the region of the squeezing device. The pressure-exerting device may be realized particularly straightforwardly in construction terms if the depth of the channel tapers, to be precise starting from the large-width inlet of the channel and extending as far as the tapered-width region of the channel, the minimal-depth region of the channel corresponding to the final insertion position of the stopper in the bottle. As soon as the bottle with the stopper positioned thereon or plugged therein passes into the region of the body, the roof slope of the channel positions the top surface of the stopper and causes the stopper to be pressed into the bottle opening as it is conveyed relative to the body. The channel region in which the minimal channel depth is achieved may then be adjoined by a constant-depth channel section which is arranged parallel to the conveying plane of the bottle. The constant-depth channel section thus causes the stopper to be kept in the position in which it is fully inserted into the bottle opening. In order to ensure that minimal frictional forces act between the stopper and the body, the body should consist of a plastic with sliding properties.
According to an advantageous configuration, it is provided that the body is slit vertically in the longitudinal direction of the channel, the slit terminating at a distance from the start of the channel. If, in the event of disruption, a bottle with stopper cannot be introduced correctly into the channel, that region of the body which acts on the stopper can spring back as a result of the slit arrangement. This prevents the bottles, which usually consist of glass, from breaking.